1. Field of the Invention
The invention concerns a travel compensation actuator, in particular for a motor vehicle clutch.
2. Description of Related Art
An actuator of this type comprises an electrical reduction motor, which operates a driving mechanism, such as for example, a pusher member acting directly or otherwise on the system to be operated, for example, a clutch pressure plate.
If the actuator is of the effort compensating type, it will generally comprise a compensating spring, which acts on a cam or an inclined ramp that is connected to the said driving mechanism so as to apply a force to this mechanism in a particular direction representing the opening of the clutch and which approximately compensates the resistance manifested by the return spring of the clutch pressure plate in such a way that effort delivered by the reduction motor for the actuation of the clutch is reduced to a minimum.
When the friction linings of the clutch start to show signs of wear, the pressure plate and thereby also the driving mechanism become displaced as a result of the modification to the travel of this element and by changes in the amount of effort needed to operate its respective actions.
Numerous systems have already been proposed to compensate wear in such mechanisms and in general these are integrated into the clutch system itself in order to compensate wear of friction linings as it occurs, so that the wear has no immediate effect on the position of the clutch pressure plate or on the travel of the driving mechanism.
However, these known solutions are all relatively complex and in practice their precision and their reliability have frequently been found wanting.
Another solution consists in adjusting the length of the driving mechanism in relation to the amount of wear shown by the linings of the clutch in such a way that this adjustment of the length has the effect of compensating the travel of the pressure plate as it becomes affected by the wear to the linings.